Understanding the basic mechanisms of normal and abnormal voice production is centrally important to the treatment of voice disorders. Glottal insufficiency from vocal fold paresis and paralysis is one of the most common voice disorders encountered in clinical medicine. Neuromuscular dysfunction leads to laryngeal left/right asymmetry and abnormalities of the two main independent variables related to glottal vibratory characteristics and acoustic output: (1) vocal fold stiffness and (2) glottal channel pre- phonatory shape (length, vertical height, and contour). A significant knowledge gap exits in our understanding of the cause-effect relationship between these aspects of glottal asymmetry and their acoustic, vibratory, and perceptual consequences. In this proposal we will systematically study laryngeal asymmetry by (1) quantifying the effects of asymmetric laryngeal activation on acoustics, aerodynamics, glottal vibration and vocal quality, (2) investigate glottal channel shape changes and their effects on vibration in paresis/paralysis conditions and in normal phonation, and (3) systematically evaluate the role of vocal fold implant stiffness and medial surface shape in the treatment of vocal insufficiency. These investigations will provide an improved knowledge base on which to build an evidence-based approach to treatment of neurogenic voice disorders.